EP1370565B1 - Method of producing 1-hydroxy-1,1-diphosphonic acid compounds - Google Patents

Abstract

In a method for preparing 1-hydroxy-1,1-diphosphonic acid compounds of the general formula I and/or of their pharmacologically compatible salts a compound of the formula II is reacted with a compound P(OSiR<SUP>5</SUP><SUB>3</SUB>)<SUB>3-p</SUB>R<SUP>6</SUP><SUB>p </SUB>and the reaction product is hydrolyzed.

Description

The present invention relates to a process for the preparation of 1-hydroxy-1,1-diphosphonic acid compounds.

The concept of "drug targeting", i. H. the targeted enrichment of drugs on site The desired effect is one that has been used in medicine and pharmacy for some time Strategy. Of particular interest here is the use of cytostatics, e.g. B. from N-mustard derivatives, such as chlorambucil (4- (4-bis (2-chloroethyl) amino) phenylbutyric acid) coupled to special alkane diphosphonic acids. Due to the high affinity of the Diphosphonic acids to apatite the skeleton become a targeted organ specificity reached. The class of such 1-hydroxy-1,1-diphosphonic acid compounds, their Production and their use as a pharmacological preparation is described in the European patent specification EP 0 170 896 B1.

According to EP 0 170 896 B1, the 1-hydroxy-1,1-diphosphonic acid compounds are prepared from the carboxylic acid chlorides by reaction with H ₃ PO ₃ in the presence of a water-releasing agent in yields of approximately 50%.

For pharmaceutical use, the 1-hydroxy-1,1-diphosphonic acid compounds have a high degree of purity, are also high for the manufacturing process Yields desired.

The compounds must also have a certain solubility for pharmaceutical use exhibit. The solubility of these compounds is very low in itself, furthermore they are Compounds partly hydrolytically unstable. An improved solubility and therefore one higher concentrations in the pharmacological preparation can be obtained, for example, via salts of the corresponding connections can be achieved. According to the state of the art corresponding salts prepared by neutralization with the equivalent amount of lye. The salts are isolated by precipitation with organic solvents, for. B. Alcohols, by crystallization or by evaporation of the (partially) neutralized solution. This procedure results in products that are often discolored. Also decompose the products partially, which results in a reduced yield, the z. T. uncharacterized decomposition products especially for use in pharmaceuticals Sector undesirable.

To isolate the salts, DE 198 20 974 A1, for example, proposes that Isolate salts using freeze drying.

The object of the present invention was based on the prior art improved process for the preparation of 1-hydroxy-1,1-diphosphonic acid compounds to provide which these compounds, for example, in higher yields supplies.

in der bedeuten

R¹

Wasserstoff, OH, NO₂, Cl, F, Br, C₁-C₆-Alkyl, das auch mit Halogen, Amino und/oder Aminoalkyl substituiert sein kann, C_1-6-Alkoxy, Aryl, Heteroaryl, eine Gruppe NR³R⁴, in der R³ und R⁴ gleich oder verschieden sein können und für Wasserstoff, C₁-C₆-Alkyl, durch Halogen substituiertes Alkyl, Hydroxy-C₁-C₆-Alkyl stehen,

R²

Wasserstoff, Halogen, Amino, das auch substituiert sein kann, C₁-C₆-Alkyl, das auch mit Halogen, Amino und/oder Aminoalkyl substituiert sein kann, C₁-C₆-Alkoxy, Aryl, Heteroaryl,

Y

O, S oder NH;

Z

C₁-C₅-Alkylen, die mit Aminogruppen substituiert sein können,

m und n

0 oder 1, mit der Maßgabe, dass, wenn n = 1, auch m = 1 ist,

worin eine Verbindung mit der Formel II

in der R¹, R², Y, Z, m und n wie oben definiert sind,
mit einer Verbindung mit der Formel III P(OSiR⁵ ₃)_3-pR⁶ _p In der bedeuten

R⁵

eine C₁-C₄-Alkylgruppe,

R⁶

eine C₁-C₆-Alkyloxygruppe,

p

0, 1 oder 2

umgesetzt, das Reaktionsprodukt in an sich bekannter Weise hydrolysiert und ggf. in die Salze überführt wird.The present invention relates to a process for the preparation of 1-hydroxy-1,1-diphosphonic acid compounds having the general formula I and / or their pharmacologically acceptable salts

in the mean

R ¹

Hydrogen, OH, NO ₂ , Cl, F, Br, C ₁ -C ₆ alkyl, which can also be substituted by halogen, amino and / or aminoalkyl, C _1-6 alkoxy, aryl, heteroaryl, a group NR ³ R ⁴ , in which R ³ and R ^{4 can be} identical or different and represent hydrogen, C ₁ -C ₆ alkyl, alkyl substituted by halogen, hydroxy-C ₁ -C ₆ alkyl,

R ²

Hydrogen, halogen, amino, which can also be substituted, C ₁ -C ₆ alkyl, which can also be substituted with halogen, amino and / or aminoalkyl, C ₁ -C ₆ alkoxy, aryl, heteroaryl,

Y

O, S or NH;

Z

C ₁ -C ₅ alkylene, which can be substituted with amino groups,

m and n

0 or 1, with the proviso that if n = 1, then m = 1,

wherein a compound of formula II

in which R ¹ , R ² , Y, Z, m and n are as defined above,
with a compound of formula III P (OSiR ⁵ ₃ ) _3-p R ⁶ _p In the mean

R ⁵

a C ₁ -C ₄ alkyl group,

R ⁶

a C ₁ -C ₆ alkyloxy group,

p

0, 1 or 2

implemented, the reaction product is hydrolyzed in a manner known per se and optionally converted into the salts.

The process according to the invention enables the production of 1-hydroxy-1,1-diphosphonic acid compounds in high yield and with such purity that the Products can also be used in pharmacological preparations. Also the further conversion to the readily soluble salts is possible.

In the compounds of the formula I, R ¹ according to the invention represents hydrogen, OH, NO ₂ , Cl, F, Br, C ₁ -C ₆ alkyl, which can also be substituted by halogen, amino and / or aminoalkyl, C _{1- 6} -alkoxy, aryl, heteroaryl, a group NR ³ R ⁴ , in which R ³ and R ^{4 may be the} same or different and for hydrogen, C ₁ -C ₆ -alkyl, halogen-substituted alkyl, hydroxy-C ₁ -C ₆ alkyl. In a preferred embodiment, R ^{1 is} a group NR ³ R ⁴ , in which R ³ and R ^{4 are} identical and each is a halogen-substituted C ₁ -C ₆ alkyl group, preferably a group -CH ₂ -CHR ⁷ Cl, where R ^{7 represents} hydrogen or a methyl group, preferably hydrogen.

Preferred halogen substituents for R ² are fluorine, chlorine or bromine. Preferred alkyl radicals or alkoxy radicals for R ² have no more than 5, in particular no more than 3, carbon atoms, and a methyl or ethyl group is preferred. The alkyl radicals or alkoxy radicals can optionally be substituted, for. B. by one or more amino groups. R ² can also represent an optionally substituted amino group. In a particularly preferred embodiment, R ^{1 represents} hydrogen, the methyl, methoxy or nitro group.

The radical R ¹ can be in the o-, m- or p-position to the part of the molecule bonded to the aromatic ring via Y. If the radical R ^{1 is} an amino group, this part of the molecule is preferably bound in the p-position, R ¹ then representing a so-called N-mustard group.

According to the invention, m and n can represent the numerical values 0 or 1, but with the Provided that if n = 1, i.e. H. one of the radicals O, S or NH is present, then m = 1. In a preferred embodiment, n = 0, i.e. the rest Y is omitted. In this Embodiment can also be n = 0.

N = 0 and m = 1 are particularly preferred, ie the alkylene radical Z is bonded directly to the aromatic ring. This straight-chain or branched and optionally substituted radical Z preferably contains not more than 5 carbon atoms, in particular not more than 3 carbon atoms, with unbranched carbon chains being preferred. An amino group is an example of a possible substituent on Z. Preferred residues for Z are the following:
-CH ₂ -, - (CH ₂ ) ₂ -, - (CH ₂ ) ₃ -, -CHCH ₃ -CH ₂ -,

A particularly preferred compound with the formula I is 4- (4- (bis (2-chloroethyl) amino) phenyl) -1-hydroxybutane-1,1-diphosphonic acid, which for brevity is called "CAD" (chlorambucil coupled to 1-hydroxy-1,1-diphosphonic acid).

To prepare the compounds of formula I according to the invention in a first Reaction step with the carboxylic acid derivatives with the formula II as starting compounds implemented a phosphorylating agent of formula III. The compounds of formula II and Formula III are preferably reacted in approximately stoichiometric amounts. Stoichiometric means that the starting compounds are approximately in a molar ratio of 1: 2 if the compound of formula II has no amino group having. The molar ratio of the compounds with formula II to the compounds with Formula III is preferably about 1: 3 when the compound of Formula II is one Contains amino group.

In order to achieve good mixing of the reactants, the reaction mixture preferably stirred.

The reaction of the compound of formula II with a compound of formula III can can be carried out over a wide temperature range from - 30 ° C to 50 ° C. The reaction is preferably carried out at a temperature of 10 to 30 ° C. temperatures are significantly above room temperature due to the formation of undesirable by-products not preferred.

In the method according to the invention, it has proven to be advantageous to connect the Formula II first in a suitable organic solvent or suspend and the compound of formula III, either as a pure compound or also in dissolved or suspended form. As a solvent to dissolve the Compounds with the formula II or III can be polar or non-polar organic Solvents such as toluene, benzene, chlorobenzene, pentane, hexane, heptane, petroleum ether, Diethyl ether, tetrahydrofuran

After adding the compound of formula III, it is preferred to add the reaction mixture to react for some time. For this purpose the temperature can be increased if necessary, whereby an after-reaction at room temperature is preferred.

The first step in the process by reacting the compounds with the formula II and III obtained reaction product can after the completion of the reaction in a conventional manner isolated or processed directly to diphosphonic acid, i.e. be hydrolyzed. Before further processing, volatile reactions (by-products) are preferably in the Vacuum removed.

The hydrolysis of the reaction product from the first process step takes place in itself known way. Preferably the reaction product is in one of the above dissolved organic solvent and water is added, if necessary with stirring, where the compound with the formula I is formed.

The compound of formula I can be isolated in a manner known per se and if necessary be cleaned by the usually insoluble reaction product from the solvent filtered off and washed with solvent if necessary.

For use in pharmacological preparations, the compounds with the Formula I preferably used in the form of its soluble salts. Both partial salts, in which only some of the four acidic protons are replaced by other cations as well Full salts and mixtures of different salts as well as mixtures of free acids with Salts can be used. Examples of pharmacologically acceptable salts are the alkali, alkaline earth and / or ammonium salts, such as sodium, potassium, magnesium, Ammonium and substituted ammonium salts. They are preferably approximately neutral reacting salts, the pH of which is between about 5 and 9 in aqueous solution. Especially the partially neutralized salts, such as the mono-, di- and trisodium salts, and the fully neutralized sodium salts of the compounds with formula I.

The compounds of the formula I can be neutralized in a manner known per se by reaction with the appropriate bases, as described, for example, in EP 0 170 896 A1 and in DE 198 20 974 A1. The aqueous solutions of the corresponding alkali, alkaline earth and ammonium compounds, such as sodium, potassium, magnesium, ammonium and substituted ammonium compounds, are preferably used, an aqueous sodium hydroxide solution being particularly preferred as the alkali. Usually, the 1-hydroxy-1,1-diphosphonic acid compounds are reacted with an equivalent amount of alkali. B. in the preparation of a tetrasodium salt, the alkali in a 4-fold molar ratio to 1-hydroxy-1,1-diphosphonic acid compounds. Accordingly, the production of disodium salts with a 2-fold molar ratio of alkali is carried out. It has proven advantageous that the 1-hydroxy-1,1-diphosphonic acid compounds are stirred into the cold, preferably from 0 ° C. to room temperature, solution of the alkali. In a preferred embodiment, the process is carried out with exclusion of O ₂ and the solution is then warmed to room temperature. Neutralization with an alkali hydride is also possible.

Neutralization can also be carried out by introducing the 1-hydroxy-1,1-diphosphonic acid compounds into an aqueous, cold sodium carbonate solution, using equivalent amounts or up to double amounts of sodium carbonate (Na ₂ CO ₃ ). Another way of producing the salts is to use ion exchangers.

In a further preferred embodiment, for the preparation of the alkali salts Compound of formula I with the corresponding alkali acetate, especially that Sodium acetate implemented. The reaction is preferably carried out at room temperature carried out.

The product obtained from the (partial) neutralization can be removed after the volatile Reaction products are processed directly, a complex insulation is in the Usually not required.

Compounds of the formula I in which R ^{1 is} hydrogen, Me, OMe, NH ₂ , NO ₂ and R ^{2 are} hydrogen, Z is a propylene group, n 0 and m 1 are new.

mit R^1' = H, Me, OMe, NH₂, NO₂.
und der Formel V

mit R^1' = H, Me, OMe, NH₂, NO₂. The present invention accordingly furthermore relates to a compound having the following formula IV:

with R ^{1 '} = H, Me, OMe, NH ₂ , NO ₂ .
and Formula V

with R ^{1 '} = H, Me, OMe, NH ₂ , NO ₂ .

Examples example 1

1.1 Presentation of the acid chlorides with SOCl ₂ according to the method known in the literature

The appropriate precautions to work under moisture and Exclusions of oxygen were made (dry diethyl ether, dry and oxygen liberated nitrogen (gas) as an inert gas atmosphere).

1.2 Presentation of the diphosphonic acids via the persilylated derivatives (for R = H, Me, OMe, NO ₂ )

Tris (trimethylsilyl) phosphite (Hata, T; Sekine, M; J. Am. Chem. Soc .; 96 (1974) 7363; Sekine, M; Okimoto, K, Yamada, K .; J. Org . Chem. 46 ( 1981) 2097) 6.7 ml (approx. 20 mmol) were added to a solution of the acid chloride (approx. 10 mmol) in 30 ml diethyl ether, stirred for 1-2 h and the volatile constituents at 80-90 ° C. in a water pump vacuum (20mbar) deducted. NMR (Et ₂ O) persilylated derivatives: ³¹ P: e.g. δ = 3.42 (R = H), 3.65 (R = NO ₂ ).

10 ml of water were added to the residue with stirring for 1 h at 80-90 ° C. and pumped to dryness in vacuo (0.1 mbar). The residue was treated with 10-15 ml of diethyl ether, the precipitate was filtered off, washed with a small amount of diethyl ether and dried (for R = H, Me, NO ₂ ). In the case of R = OMe, the residue was treated with ethyl acetate, washed with a minimum of ethyl acetate and dried. A diphosphonic acid-diethyl ether complex (1: 1) was formed for R = NO ₂ , which was converted into the pure acid by heating for 2 h at 80-90 ° C. with pumps at 0.1 mbar.
Mp diphosphonic acid R = H (C ₁₀ H ₁₆ O ₇ P ₂ , 310.18) 183-185 ° C (yield 75% based on the corresponding acid chloride); NMR: ¹ H (DMSO-d ₆ ): δ = 1.86 (m, 4H, C H ₂ C H ₂ CH ₂ ), 2.51 (m, 2H, C H ₂ CO), 7.18 (m , 5H, Ph), 10.20 (5H, br, OH); ³¹ P (DMSO-d ₆ ): δ = 21.63 ( ³ J _RH = 14.0 Hz). MS: (FAB, m / z %): FAB ⁺ 311 (M ⁺ + H); FAB ^- 309 (M ^- - H); R = Me (C ₁₁ H ₁₈ O ₇ P ₂ , 324.20) 175-177 ° C (71%) NMR: ¹ H (DMSO-d ₆ ): δ = 1.86 (m, 4H, C H ₂ C H ₂ CH ₂ ), 2.24 (3H, Me), 2.44 (2H, C H ₂ CO), 7.04 (m, 4H, Ph), 9.06 (5H, br, OH); ³¹ P (DMSO-d _s ): δ = 21.35 ( ³ J _PH = 13.90 Hz). MS: (FAB, m / z %): FAB ⁺ 325 (M ⁺ + H); FAB ^- 323 (M ^- - H); R = OMe (C ₁₁ H ₁₈ O ₈ P ₂ , 340.20) 173-175 ° C (67%) NMR: ¹ H (DMSO-d ₆ ): δ = 1.88 (m, 4H, C H ₂ C H ₂ CH ₂ ), 2.54 (2H, C H ₂ CO), 3.75 (3H, OMe), 6.90 (2H, AB, Ph), 7.10 (2H, AB, Ph), 10.15 (5H, br, OH); ³¹ P (DMSO-d ₆ ): δ = 21.22 ( ³ J _PH = 13.0 Hz). MS: (FAB, m / z %): FAB ⁺ 341 (M ⁺ + H); FAB ^- 339 (M ^- - H); R = NO ₂ 172-174 ° C (70%) (C ₁₀ H ₁₅ NO ₉ P ₂ , 355.17) NMR: ¹ H (DMSO-d ₆ ): δ = 1.90 (4H, C H ₂ C H ₂ CH ₂ ), 2.69 (2H, C H ₂ CO), 6.50 (2H, AB, Ph), 8.15 (2H, AB, Ph), 10.37 (5H, br, OH); ³¹ P (DMSO-d ₆ ): δ = 21.15 ( ³ J _PH = 13.0 Hz). MS: (FAB, m / z %): FAB ⁺ 356 (M ⁺ + H); FAB ^- 354 (M ^- - H).

Example 2

2.1 Preparation of chlorambucil hydrochloride C ₁₄ H ₁₉ Cl ₄ NO [359.24] according to Firestone, RA et al., J. Med. Chem. 1984, 27 1037

Oxalyl chloride 5.2 ml (approx. 60 mmol) became a stirred solution of 1.82 g (approx. 6 mmol Chlorambucil in 30 ml methylene chloride given at 0 ° C together with a drop of DMF (Dimethylformamide). It was stirred at the same temperature for 30 min, then for 1.5 h at room temperature and to dry in a water bath (40-50 ° C) in Water jet pump vacuum (20 mbar) deducted, then at the same temperature in Vacuum (0.1 mbar). The yield of chlorambucil hydrochloride 2.16 g (slightly yellow Solid) was quantitative.

2.2 Preparation of Persilylated Chlorambucil-Diphosphonic Acid C ₂₉ H ₆₃ Cl ₂ NO ₇ P ₂ Si ₅ [811.12]

Tris (trimethylsilyl) phosphite 6.0 ml (approx. 18 mmol) was added with stirring to a suspension of the acid chloride hydrochloride (approx. 6 mmol) in 30 ml of diethyl ether at room temperature, stirred for 1-2 h (after 30-60 min the suspension disappeared) and the volatile constituents were drawn off at 80-90 ° C. (0.1 mbar) for 2-3 h. The residue was an oily liquid. Yield 4.9 g, almost quantitative. NMR (Et ₂ O): ³¹ P: δ = 4.09.

2.3 Preparation of chlorambucil diphosphonic acid C ₁₄ H ₂₃ Cl ₂ NO ₇ P ₂ [450.19]

6 ml of water were added to the oily liquid from 2.2 . The reaction mixture was left for 3-4 hours until the solid formed had disappeared, then dried at 45-50 ° C. in vacuo (0.1 mbar). The remaining solid was heated to boiling with ethyl acetate, then filtered off and dried again in vacuo (0.1 mbar) at 45-50 ° C. Mp 155-165 ° C, yield 2.7 g, almost quantitative. NMR: ¹ H (DMSO-d ₆ ): δ = 1.80 (m, 4H, C H ₂ C H ₂ CH ₂ ), 2.38 (m, 2H, C H ₂ CO), 3.66 (8H , CH ₂ ), 6.66 (2 H, AB, Ph), 6.98 (2 H, AB, Ph), 9.50 (5H, br, OH); ³¹ P (DMSO-d ₆ ): δ = 21.48 ( ³ J _PH = 14.0 Hz). MS: (FAB, m / z ): FAB ^- 448 (M ^- - H).

2.4 Preparation of Sodium Chlorambucil Diphosphonate C ₁₄ H ₂₂ Cl ₂ NNaO ₇ P ₂ [472.17]

Chlorambucil-diphosphonic acid (2.25 g, approx. 5 mmol) from 2.3 was slurried in 6 ml of water and 0.95 g (7 mmol) sodium acetate was added and left under stirring for 15-20 h. The white product was filtered off, washed with 3x1 ml of water and 3x5 ml of ethanol, first dried in air and then in vacuo at 40 ° C. Yield 1.88 g (80%). NMR: ¹ H (CF ₃ COOD): δ = 2.20 (m, 4H, C H ₂ C H ₂ CH ₂ ), 2.80 (m, 2H, C H ₂ CO), 3.42 (2H, CH ₂ ), 3.80 (2H, CH ₂ ), 4.14 (4H, 2CH ₂ ), 7.54 (4 H, br, Ph); ³¹ P (CF ₃ COOD): δ = 22.38 ( ³ J _PH = 14.0 Hz). MS: (FAB, m / z %): FAB ⁺ 23 (Na ⁺ ); FAB ^- 470 (M ^- -H).

Claims (7)

1. Process for preparing 1-hydroxy-1,1-diphosphonic acid compounds having the general formula I and/or the pharmacologically acceptable salts thereof

   

   in which

   R¹

   is hydrogen, OH, NO₂, Cl, F, Br, C₁-C₆-alkyl, which may also be substituted by halogen, amino and/or aminoalkyl, C₁-C₆-alkoxy, aryl, heteroaryl, a group NR³R⁴, in which R³ and R⁴ may be identical or different and are hydrogen, C₁-C₆-alkyl, halogen-substituted alkyl, hydroxy-C₁-C₆-alkyl,

   R²

   is hydrogen, halogen, amino, which may also be substituted, C₁-C₆-alkyl, which may also be substituted by halogen, amino and/or aminoalkyl, C₁-C₆-alkoxy, aryl, heteroaryl,

   Y

   is O, S or NH,

   Z

   is C₁-C₅-alkylene, which may be substituted by amino groups,

   m and n

   are 0 or 1, with the proviso that if n = 1, m is also = 1,

   wherein a compound having the formula II

   

   in which R¹, R², Y, Z, m and n are as defined above, is reacted with a compound having the formula III P(OSiR⁵ ₃)_3-pR⁶ _p in which

   R⁵

   is a C₁-C₄-alkyl group,

   R⁶

   is a C₁-C₆-alkyloxy group,

   p

   is 0, 1 or 2,

   the reaction product is hydrolysed in a manner known per se and possibly converted to the salts.
2. Process according to Claim 1, characterized in that the compound having the formula I is 4-(4-(bis-(2-chloroethyl)amino)phenyl)-1-hydroxybutane-1,1-diphosphonic acid.
3. Process according to Claim 1 or 2, characterized in that in formula III, p is 0.
4. Process according to any of Claims 1 to 3, characterized in that the compounds having the formula II and the formula III are reacted in approximately stoichiometric amounts.
5. Process according to any of Claims 1 to 4, characterized in that in order to prepare the salts, the compounds having the formula I are neutralized or partially neutralized with aqueous solutions of the corresponding alkali, alkaline-earth and ammonium compounds, such as sodium, potassium, magnesium, ammonium and substituted ammonium compounds, or with alkaline acetate.
6. Compound having the following formula (IV)

   

   where R^1' = H, Me, OMe, NH₂, NO₂.
7. Compound having the following formula (V)

   

   where R^1' = H, Me, OMe, NH₂, NO₂.